Back pressure valve



19.40- J. c. FORTUNE BACK PRESSURE VALVE Filed Feb. 15, 1957 [m n 1 3 1rm C 2 I 5 2 m 0/ x J Om 7 I MW w. a dwafiifi d wm J H 9 0 I L I w W W 23 7 M 9 Patented Jan. 2, 1940 UNITED STATES BACK PRESSURE VALVE James C.Fortune, Houston, Tex, assignor to .Reed

Roller Bit Company, Houston, Tex, a corporation of Texas ApplicationFebruary 15, 1937, Serial No. 125,809

' 8 Claims.

customary to employ a string of pipe known as the drill stem, with a biton the lower end thereof, and means at the upper end thereof forrotating 10 the pipe and causing rotation of the bit. During thedrilling operations it is necessary to circulate a fluid through thewell, and this is ordinarily done by circulating the fluid downwardlythrough the drill stem and out through holes properly 16 located withrespect to the cutting portions of the bit, this fluid then passingupwardly through the drill hole about the drill stern and washing thecuttings upwardly therewith. Under many circumstances, it is highlydesirable, if not impera- 20 tive, that some means be provided withinthe drill stem for preventing a backward flow of this Washing fluidupwardly through the drill stem. Various means are employed forcontrolling flow upwardly through the well around the outside of thedrill stem, and it is necessary also to have some means within the drillstem so that 'in the event a high pressure formation is encountereddining the drilling operation, this high pressure will. be preventedfrom blowing out through the drill stem. Furthermore, by the use of acheck valve adjacent the lower end of the drill stem, the same may bekept empty or partially so and its buoyancy employed to float it intothe well. Various types of valves have heretofore been employed for thepurpose set forth. For the most part, these have consistedof balls orother valvelike members adapted to seat against a separate seat withinthe drill stem, and to move away from said seat upon downward. flow offluid through the drill stem. Naturally, valves of this type restrict toa considerable extent the cross section area of the interior of the.drill stem at the point where the valve and the seat overlap radiallytherein. If the bore of the drill stem were restricted, for example, toprovide a shoulder against which the ball or like valve member couldseat, that would in itself provide a considerable restriction in thecross section area available for fluid flow. If on the other hand thebore of the drill stem were enlarged to provide the shoulder againstwhich such a valve would seat, the valve would have to be made larger indiameter than the normal bore-of the drill stem in order to seat againstsuch a seat, and the valve seat would itself in such instances prove ameans of restricting the available cross section area of the drill stem.

It is an object of this invention. to provide a back pressure valve fora drill stem or other like conduit, in which the passageway through the5 drill stem may be made of the largest possible diameter and the valvemember may be made of the smallest possible diameter with respectthereto.

It is a further object to provide a back pressure 10 valve for a drillstem or the like which when opened will provide a maximum cross sectionarea available for fluid flow through the drill stem.

It is a further object of this invention to pro- 15 vide a back pressurevalve for adrill stem, which valve will offer the least possibleresistance, to

flow of fluid through the drill stem.

Another object is to provide a valve of the nature set forth which willbe to the greatest pos 20 sible extent durable and trouble-free.

It is a further object to provide a valve'in which worn parts may bereplaced with a minimum of time and labor.

Other objects and advantages of this invention 25 will become apparentfrom the following description taken in connection with the accompanyingdrawing, it being understood that said description and drawing are byway of illustration only, and that they are not to be taken as in anyway a 30 limitation upon the scope of this invention. Such scope is tobe limited only by the prior art, and by the terms of the appendedclaims.

In the drawing:

Fig. 1 is a view partly in vertical cross sec- 35 tion illustrating asection of drill pipe in which is installed a valve constructed inaccordancewith this invention.

construction which is used for joining together the ends of two sectionsof drill pipe. These tool joint sections I and 2 are ordinarily threadtoedly connected to each other.

At 3 there is illustrated a fitting which is inserted between the tooljoint sections l a d 2. This fitting 3 is internally threaded at itsupper end to receive the pin section I of the tool joint, 55

and is externally threaded at' its lower end .to threadedly engage thebox section 2 of the tool joint. This fitting 3 and a portion of thesection I constitute the valve housing, to house the valve, which is tobe interposed in the drill stem.

Within its upper end, the fitting 3 is provided with a relatively shortzone having an internal diameter slightly greater than the innerdiameter of the tool joint sections I and 2. Just below this zone 4 is asecond zone 5 of somewhat greater extent longitudinally than the zone 4and of a larger diameter, the zone 5 being joined to the zone 4 by atapered portion 6. Below the lower end of the zone 5 is a third zone 1which is of substantially the same diameter as the zone 4, and which isjoined to the zone 5 by a tapered section 8. The lower portion of thefitting 3 is formed with an internal diameter 9 which is preferablysubstantially the same as the internal diameter of the zone through thetool joint. This lower portion is joined to the zone I by a tapered vsection III.

The valve element which is positioned within the special fitting 3consists principally of a body portion I I having a tapered upwardlypresented nose I2 thereon, and having a groove thereabout as shown at I3for the purpose of receiving a packing cup I4. Formed on the bodyportion II just below the packing cup I4 and providing the lower wall ofthe groove I 3 is an upwardly facing shoulder I 5. This shoulder is ofsufllciently small radial extent to provide space for the lower taperededge portion I6 of the packing. Above the packing I4 and forming theupper wall of the groove I3 is a laterally extending flange I I. Thisflange is of only slightly less radial extent than the packing itself soas to form a substantially complete axial support for the packing toprevent the packing from being washed ofl the body I I in an upwardlydirection. It is to be noted that the packing is of substantially thesame external diameter as the internal diameter 01'- the bore I8 of thetool joint section I.

On the lower end of the body portion II there are 'formed a plurality ofradially extending vanes or guide wings I9, these wings preferably beingbeveled at their outer lower corners as shown at 20, and provided withenlarged heads or abutments adjacent their upper outer comers asillustrated at 2|.

The form of the valve element illustrated in Fig. 3 is similar to thatillustrated in Figs. 1 and 2, except for the fact that the upper end ofthe body portion II instead of being formed integral with the nose ofthe body portion is connected to the separablenose portion I2 by meansof screw threaded connection 22. In this instance, the groove which isformed between the body portion II and the nose portion I2 is ofdovet'ail cross sectionas illustrated at I3. The packing I4 iscorrespondingly shaped, and is provided with a downwardly extending lipI6, this packing being locked in position when the nose I2 is threadedlyengaged with the body portion II. v

In operation, during the time that the wash-' ing fluid is being pumpeddownwardly through 'the drill stem, the valve element will occupy theposition illustrated in Fig. 2. When in this posi tion, the beveledlower corners of the guiding wings I9 will contact the tapered sectionI0 joining the-zone I with the lower portion 9 of the fitting 3, andwill maintain the valve element in such position that the packing I4 andthe shoulder I I, which form the largest cross section area crosssectional area may be so controlled that it will very closely approachand in the smaller sizes-actually exceed the cross section area of thepassage through the tool joint. In this connection, it is noted that theexternal diameter of the packing I4 is limited to substantially the samevalue as the internal diameter of the tool joint section I, while theinternal diameter of the zone 5 is limited only by the strength of thematerial of which the fitting 3 is formed.

When the downward flow through the drill stem ceases and upward flowbegins. the upward flow' will raise the valve element until the packingenters the bore through the tool joint section I, and the upper ends 2Iof the wings I9 on the valve element engage with the end of the tooljoint section I. When this occurs, the pressure below the valve elementwill expand the packing cup I4 and press the lower lip I6 thereofagainst the inner wall of the tool joint section I, thus preventingfurther upward flow through the drill stern.

From the foregoing it will be noted that a back pressure valvecombination has been provided in which there is no restriction orreduction of thesize of the normal fluid conducting bore for the purposeof forming a valve seat, and that the valve element which is provided isof no greater diameter than the bore which is normally provided for theconduction of fluid. In fact, the valveelement is of a diameter which iscapable of passing through any portion of the fluid conductingpassageway. It only seals against the walls of this passageway when itis stopped by the wings I9 in such a position that it lies within thesmallest portion of the passageway.

When moved to its open position within the enlarged zone 5 provided forreceiving the valve element when downward flow is taking place, thisvalve element offers the least possible resistance to the flow of fluidinasmuch as it is provided with a stream-lined front or upper end, andis of the least possible diameter for performing thethe passagewaythrough this seat, and hence would be larger than the minimum passagewayavailable for the flow of fluid. In the present construction, the valveelement is actually of no greater diameter than the minimum diameter ofthe passageway'available for the flow of fluid. Because of the fact thatthe valve is of the least possible diameter with respect to the minimuminternal diameter of the drill stem, the area available for the flow offluid about the valve element when the valve is openis the maximum areawhich could be obtained. 7,

It will thus be appreciated that while a valve element has-been providedwhich is thoroughly emcient and capable of withstanding any back,

which at the same time offers the least possible resistance to flow whenit is in its open position.

Having described my invention, I claim:

1. In a back pressure valve for a drill pipe, a valve housing comprisinga fitting adapted to be connected between adjacent sections of the drillpipe, said housing including an adjacent end portion of one of saidsections having a passage therethrough, a portion of which is of adiameter greater than the portion of the passage through said adjacentend portion, a valve element in said housing passage of a diameter lessthan the diameter of the passage through the said end portion and havinga skeleton part in the passage through said housing of a diameter toogreat to enter said end portion, whereby movement of said valve elementinto said end portion will be limited, and said valve element having apart expansible into sealing engagement with the walls of said endportion when forced thereinto by fluid under pressure tending to entersaid end portion from said fitting.

2. In a back pressure valve for a drill pipe, a valve. housingcomprising a fitting having threaded pin and box portions at itsopposite ends, respectively, adapted to receive the respective sectionsof a tool joint, said housing including an adjacent end portion of thatone of said sections which is adapted to be secured to the upper end ofthe fitting and having a passage therethrough, the upper portion of thepassage through the fitting being of a diameter greater than the portionof the passage through said adjacent end portion, a valve element insaid housing passage of a diameter less than the minimum diameter of thepassage through the said end portion and having a skeleton part in thepassage through said housing of a diameter too great to enter said endportion, whereby movement of said valve element into said end portionwill be limited, and said valve element having apart expansibleinto-sealing engagement with the walls of said end portion when forcedthereinto by fluid under pressure tending to enter said end portion fromsaid fitting.

3. In a back pressure valve for a drill pipe, a valve housing comprisinga fitting adapted to be connected between adjacent sections of the drillpipe, said housing including an adjacent end portion of one of saidsections and having a passage therethrough, a portion of which is of adiameter greater than the portion of the passage through said adjacentend portion,- a valve element in said housing passage of a. diameterless than the diameter of the passage through the said end portion andhaving a skeleton part in the passage through said housing of a diametertoo great to enter said end portion, whereby movement of said valveelement into the said end portion will be limited, and said valveelement having a sealing cup expansible into sealing engagement with thewalls of said end portion when forced thereinto by fluid underpressuretending to enter said end portion from said fitting.

4. In a back pressure valve for a drill pipe, a valve housing comprisinga fitting having threaded pin and box portions in its opposite ends,respectively, adapted to receive the respective sections of a tooljoint, said housing including anadjacent end portion of that one of saidsections which is adapted to be secured to the upper end of the fittingand having a passage therethrough, the upper portion of the passagethrough the fitting being of a diameter greater than the portionof thepassage through said adjacent end portion, a valve element in saidhousing passage of a diameter less than the minimum diameter of thepassage through said end portion and having a skeleton part in thepassage through said housing of a diameter too great to enter said endportion, whereby movement of said valve element into said end portionwill be limited, and said valve element having a sealing cup expansibleinto engagement with the walls of said end portion when forced thereintoby fluid under pressure tending to enter said end portion tion and thelower portion of which is of a smaller diameter than the passage throughthe said upper portion of the fitting, a valve element in said housingpassage of a diameter less than the minimum diameter of the passagethrough said end portion and having a skeleton part in the upper portionof the passage through said fitting of a diameter too great to entersaid end portion or said lower portion of the fitting, whereby movementof said valve element into said end portion will be limited and movementinto the lower portion of said fitting will be prevented, and said valveelement having a part expansible into sealing engagement with the wallsof said end portion when forced thereinto by fluid under pressuretending to enter said end portion from said fitting.

6. In a back pressure valve for a drill pipe, a valve housing comprisinga fitting adapted to be connected between adjacent sections of the drillpipe, said housing including an adjacent end portion of one of saidsections and having a passage therethrough, a portion of which is of a.diameter-greater than the portion of the passage through said adjacentend portion, a valve element in said housing passage of a diameter lessthan the diameter of the passage through the said end portion and havinga skeleton part in the passage through said housing of a diameter toogreat to enter said end portion, whereby movement of said valve element'into said end portion will be limited, and said valve element having apart expansible into sealing engagement with thewalls of said endportion when forced thereinto by fluid under pressure tending to entersaid end portion from said fitting, said skeleton part and the remainderof said valve element being joined together to form a dart-like elementand said valve element having a streamlined upper end to facilitate flowof fluid past the same when it is located within the larger portion ofsaid passage through the housing. v

7. In a back pressure valve for a drill pipe, a valve housing comprisinga fitting adapted to be connected between adjacent sections of the drillpipe, said housing including an adjacent end portion of one of saidsections and having a. passage therethrough, a portion of which is of adiameter of the passage through said adjacent end porgreater than theportion of the passage through tion and having a skeleton part in'thepassage through said housing of a diameter too great to enter said endportion, whereby movement of said valve element of the said. endportionwill be limited, and said valve element having a sealing cupexpanslble into sealing engagement with the walls of said end portionwhen forced thereinto valve housing comprising a fitting adapted to beconnected between adjacent sections of said drill pipe, said housingincluding an adjacent .end portion of one of said sections and having apassage therethrough, a portion of which is of a diameter greater thanthe portion of thepassage through said adjacent end portion, a valveelement in said housing passage of a diameter less than the diameter ofthe passage through said end portion and having a skeleton part joinedthereto and disposed in the passage through said housing, said skeletonpart being of a diameter too great to enter said end portion, wherebymovement of said valve element into said end portion will be limited,said valve element being formed in two separable parts and having anexpansible sealing cup disposed between said parts and expansible intosealing engagement with the walls of said end portion when forcedthereinto by fluid under pressure tending to enter said end portion fromsaid fitting.

JAMES C. FORTUNE.

